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Geniman MP, Morozova OB, Lukzen NN, Grampp G, Yurkovskaya AV. Marcus Cross-Relationship Probed by Time-Resolved CIDNP. Int J Mol Sci 2023; 24:13860. [PMID: 37762162 PMCID: PMC10530771 DOI: 10.3390/ijms241813860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/04/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
The time-resolved CIDNP method can provide information about degenerate exchange reactions (DEEs) involving short-lived radicals. In the temperature range from 8 to 65 °C, the DEE reactions of the guanosine-5'-monophosphate anion GMP(-H)- with the neutral radical GMP(-H)•, of the N-acetyl tyrosine anion N-AcTyrO- with a neutral radical N-AcTyrO•, and of the tyrosine anion TyrO- with a neutral radical TyrO• were studied. In all the studied cases, the radicals were formed in the reaction of quenching triplet 2,2'-dipyridyl. The reorganization energies were obtained from Arrhenius plots. The rate constant of the reductive electron transfer reaction in the pair GMP(-H)•/TyrO- was determined at T = 25 °C. Rate constants of the GMP(-H)• radical reduction reactions with TyrO- and N-AcTyrO- anions calculated by the Marcus cross-relation differ from the experimental ones by two orders of magnitude. The rate constants of several other electron transfer reactions involving GMP(-H)-/GMP(-H)•, N-AcTyrO-/N-AcTyrO•, and TyrO-/TyrO• pairs calculated by cross-relation agree well with the experimental values. The rate of nuclear paramagnetic relaxation was found for the 3,5 and β-protons of TyrO• and N-AcTyrO•, the 8-proton of GMP(-H)•, and the 3,4-protons of DPH• at each temperature. In all cases, the dependences of the rate of nuclear paramagnetic relaxation on temperature are described by the Arrhenius dependence.
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Affiliation(s)
- Maksim P. Geniman
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia; (M.P.G.); (O.B.M.); (N.N.L.)
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Olga B. Morozova
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia; (M.P.G.); (O.B.M.); (N.N.L.)
| | - Nikita N. Lukzen
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia; (M.P.G.); (O.B.M.); (N.N.L.)
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Günter Grampp
- Institute of Physical and Theoretical Chemistry, Graz University of Technology, Stremayrgasse, 9, A-8010 Graz, Austria;
| | - Alexandra V. Yurkovskaya
- International Tomography Center SB RAS, 630090 Novosibirsk, Russia; (M.P.G.); (O.B.M.); (N.N.L.)
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
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Reduction of thymine radicals by Tryptophan: A study of CIDNP kinetics. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2021.113761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Temperature dependence of the degenerate electron exchange between guanosine-5′-monophosphate cation and its short-lived radical dication in aqueous solution. Russ Chem Bull 2022. [DOI: 10.1007/s11172-021-3356-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Boelens R, Ivanov K, Matysik J. Introduction to a special issue of Magnetic Resonance in honour of Robert Kaptein at the occasion of his 80th birthday. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:465-474. [PMID: 37904778 PMCID: PMC10539797 DOI: 10.5194/mr-2-465-2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Indexed: 11/01/2023]
Abstract
This publication, in honour of Robert Kaptein's 80th birthday, contains contributions from colleagues, many of whom have worked with him, and others who admire his work and have been stimulated by his research. The contributions show current research in biomolecular NMR, spin hyperpolarisation and spin chemistry, including CIDNP (chemically induced dynamic nuclear polarisation), topics to which he has contributed enormously. His proposal of the radical pair mechanism was the birth of the field of spin chemistry, and the laser CIDNP NMR experiment on a protein was a major breakthrough in hyperpolarisation research. He set milestones for biomolecular NMR by developing computational methods for protein structure determination, including restrained molecular dynamics and 3D NMR methodology. With a lac repressor headpiece, he determined one of the first protein structures determined by NMR. His studies of the lac repressor provided the first examples of detailed studies of protein nucleic acid complexes by NMR. This deepened our understanding of protein DNA recognition and led to a molecular model for protein sliding along the DNA. Furthermore, he played a leading role in establishing the cluster of NMR large-scale facilities in Europe. This editorial gives an introduction to the publication and is followed by a biography describing his contributions to magnetic resonance.
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Affiliation(s)
- Rolf Boelens
- Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Konstantin Ivanov
- International Tomography Center, Siberian Branch of the Russian
Academy of Sciences, Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University,
Novosibirsk 630090, Russia
| | - Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstraße 3, 04189 Leipzig, Germany
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Nitschke P, Lokesh N, Gschwind RM. Combination of illumination and high resolution NMR spectroscopy: Key features and practical aspects, photochemical applications, and new concepts. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:86-134. [PMID: 31779887 DOI: 10.1016/j.pnmrs.2019.06.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/04/2019] [Accepted: 06/04/2019] [Indexed: 06/10/2023]
Abstract
In the last decade, photochemical and photocatalytic applications have developed into one of the dominant research fields in chemistry. However, mechanistic investigations to sustain this enormous progress are still relatively sparse and in high demand by the photochemistry community. UV/Vis spectroscopy and EPR spectroscopy have been the main spectroscopic tools to study the mechanisms of photoreactions due to their higher time resolution and sensitivity. On the other hand, application of NMR in photosystems has been mainly restricted to photo-CIDNP, since the initial photoexcitation was thought to be the single key to understand photoinduced reactions. In 2015 the Gschwind group showcased the possibility that different reaction pathways could occur from the same photoexcited state depending on the reaction conditions by using in situ LED illumination NMR. This was the starting point to push the active participation of NMR in photosystems to its full potential, including reaction profiling, structure determination of intermediates, downstream mechanistic studies, dark pathways, intermediate sequencing with CEST etc. Following this, multiple studies using in situ illumination NMR have been reported focusing on mechanistic investigations in photocatalysis, photoswitches, and polymerizations. The recent increased popularity of this technique can be attributed to the simplicity of the experimental setup and the availability of low cost, high power LEDs. Here, we review the development of experimental design, applications and new concepts of illuminated NMR. In the first part, we describe the development of different designs of NMR illumination apparatus, illuminating from the bottom/side/top/inside, and discuss their pros and cons for specific applications. Furthermore, we address LASERs and LEDs as different light sources as well as special cases such as UVNMR(-illumination), FlowNMR, NMR on a Chip etc. To complete the discussion on experimental apparatus, the advantages and disadvantages of in situ LED illumination NMR versus ex situ illumination NMR are described. The second part of this review discusses different facets of applications of inside illumination experiments. It highlights newly revealed mechanistic and structural information and ideas in the fields of photocatalyis, photoswitches and photopolymerization. Finally, we present new concepts and methods based on the combination of NMR and illumination such as sensitivity enhancement, chemical pump probes, experimental access to transition state combinations and NMR actinometry. Overall this review presents NMR spectroscopy as a complementary tool to UV/Vis spectroscopy in mechanistic and structural investigations of photochemical processes. The review is presented in a way that is intended to assist the photochemistry and photocatalysis community in adopting and understanding this astonishingly powerful in situ LED illumination NMR method for their investigations on a daily basis.
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Affiliation(s)
- Philipp Nitschke
- Organic Chemistry, University of Regensburg, 93040 Regensburg, Germany
| | | | - Ruth M Gschwind
- Organic Chemistry, University of Regensburg, 93040 Regensburg, Germany.
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Zheng L, Zhao M, Xiao C, Zhao Q, Su G. Practical problems when using ABTS assay to assess the radical-scavenging activity of peptides: Importance of controlling reaction pH and time. Food Chem 2015; 192:288-94. [PMID: 26304349 DOI: 10.1016/j.foodchem.2015.07.015] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 06/18/2015] [Accepted: 07/06/2015] [Indexed: 11/28/2022]
Abstract
Effects of reaction pH and time on the antioxidant behaviors of Tyr, Trp, Cys, and their related peptides (Tyr-Gly, Tyr-Glu, Tyr-Lys, Trp-Gly, Trp-Glu, Trp-Lys, Cys-Gly and Cys-Gly) in ABTS assay were investigated. Results showed that all these amino acids and peptides displayed a biphasic kinetic pattern with a fast initial step and a slow secondary step. The initial reaction rates of Tyr, Trp and their related peptides were strongly dependent on pH, while those of Cys and Cys-containing peptides were unaffected by pH. They failed to reach equilibrium over the short incubation period of 6-10 min typically used in this assay. Longer incubation time was needed for most of the peptides to approach equilibrium at lower pH. The observed biphasic kinetic pattern as well as the high TEAC values for these amino acids and peptides, could be a result of combined antioxidant behaviors of themselves plus the generated reaction products.
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Affiliation(s)
- Lin Zheng
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China; Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou 510640, China
| | - Mouming Zhao
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China; Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou 510640, China; State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China
| | - Chuqiao Xiao
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China; Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou 510640, China
| | - Qiangzhong Zhao
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China; Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou 510640, China
| | - Guowan Su
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, China; Guangdong Food Green Processing and Nutrition Regulation Technologies Research Center, Guangzhou 510640, China.
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Abramova TV, Morozova OB, Silnikov VN, Yurkovskaya AV. Synthesis of nucleotide-amino acid conjugates designed for photo-CIDNP experiments by a phosphotriester approach. Beilstein J Org Chem 2013; 9:2898-909. [PMID: 24367455 PMCID: PMC3869286 DOI: 10.3762/bjoc.9.326] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 11/15/2013] [Indexed: 11/23/2022] Open
Abstract
Conjugates of 2’-deoxyguanosine, L-tryptophan and benzophenone designed to study pathways of fast radical reactions by the photo Chemically Induced Dynamic Nuclear Polarization (photo-CIDNP) method were obtained by the phosphotriester block liquid phase synthesis. The phosphotriester approach to the oligonucleotide synthesis was shown to be a versatile and economic strategy for preparing the required amount of high quality samples of nucleotide–amino acid conjugates.
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Affiliation(s)
- Tatyana V Abramova
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, Lavrent'ev Ave, 8, Novosibirsk 630090, Russia ; Novosibirsk State University, Pirogova St. 2, Novosibirsk 630090, Russia
| | - Olga B Morozova
- Novosibirsk State University, Pirogova St. 2, Novosibirsk 630090, Russia ; International Tomography Center, SB RAS, Institutskaya 3a, Novosibirsk 630090, Russia
| | - Vladimir N Silnikov
- Institute of Chemical Biology and Fundamental Medicine, SB RAS, Lavrent'ev Ave, 8, Novosibirsk 630090, Russia
| | - Alexandra V Yurkovskaya
- Novosibirsk State University, Pirogova St. 2, Novosibirsk 630090, Russia ; International Tomography Center, SB RAS, Institutskaya 3a, Novosibirsk 630090, Russia
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